A sixteen-year-old boy suffered from sharp pain in the knee during a jump while playing basketball. He had a positive history of Osgood Schlatter disease. Radiographic evaluation demonstrated an avulsion fracture of the tibial tuberosity Type III according to the classification of Watson-Jones. Rehabilitation after avulsion fracture of the tibial tuberosity is an important consideration for this relatively uncommon adolescent injury. In such avulsion fractures, landing on the ground with the knee fully extended after a jump is the most likely cause. This case report reviews the rehabilitation program, and selected functional outcome measures after rehabilitation are reported. The patient returned to sporting activity after 12 months.